Periodic TableAll elementsPhosphorus
No. 015
P
30.974 u
Element · Reactive Nonmetal

Phosphorus

Phosphorus (磷, symbol P) is chemical element number 15, a Reactive Nonmetal in period 3, group 15 of the periodic table, with a standard atomic weight of about 30.974. Essential for DNA, RNA, and ATP. Multiple allotropes including white, red, and black.

Period 3Group 15[Ne] 3s² 3p³

Properties

Atomic number15
SymbolP
Atomic mass30.974 u
CategoryReactive Nonmetal
Period3
Group15
Electron configuration[Ne] 3s² 3p³
Electronegativity2.19
Covalent radius107 pm
Density1.82 g/cm³
Melting point317.3 K
Boiling point550 K
DiscoveryHennig Brand, 1669

Overview

Essential for DNA, RNA, and ATP. Multiple allotropes including white, red, and black. Phosphorus (P) holds position 15 in the periodic table, a Reactive Nonmetal in period 3, group 15. As a nonmetal it tends to gain electrons, or to share them with other nonmetals when bonding.

It has the configuration [Ne] 3s² 3p³ and an electronegativity near 2.19; its 5 outer-shell electrons drive its bonding. Under standard conditions it exists as a solid (a very low melting point); it melts near 317.3 K (44.2 °C), boils near 550 K (276.9 °C), has a density around 1.82 g/cm³.

It is widely used in Agriculture / Fertiliser and Medical / Pharma. On the safety side, it carries a moderate hazard rating. It was first described by Hennig Brand in 1669. Browse elements of the same category in the browse view.

Electron shells

P15

Electrons per shell: 2 · 8 · 5

Main uses

Hazard

ModerateFlammable, Toxic

Compounds containing Phosphorus

No compounds in this knowledge base contain Phosphorus yet.

Data sources

Atomic mass uses IUPAC (CIAAW) standard atomic weights; the covalent radius is from Cordero et al. (2008). Verify on the RSC Periodic Table, PubChem and Wikipedia. Educational reference only.